Classical wide angle lenses with high apertures generally have more than six lenses, in which, as a result of the use of negative refractive power in the front section, a focal intercept length is maintained that is large relative to the focal distance, while the relative luminous intensity is increased through the intentionally introduced aperture diaphragm aberration with increasing image angle. As the expert knows, the characteristic design of the front element is a result of a compromise in respect to distortion correction and the introduction of aperture diaphragm aberration. Given the restriction to spherical surfaces in the design of high aperture lenses with large image angle, acceptable image quality can be achieved only through the use of a large number of lenses. By utilizing aspherical surfaces, the number of lenses can be decreased through the corrective degrees of freedom associated with this.
5-lens designs with a maximum image angle of 85 are described in DE-OS 25 47 713. 3- to 7-lens wide angle systems for endoscopes are presented in DE-OS 36 00 573; the 4-lens systems discussed in the latter attain a maximum image of 95.degree., and the 5-lens system mentioned has an image angle of 106.degree., whereas the 6- and 7-lens wide angle systems possess a maximum image angle of 120.degree.. Accordingly, it should be borne in mind that, to date, a maximum image angle of only 95.degree. was attained when using a 4-lens solution.